Screening device



April 30, 1935. c. s. LINCOLN 1,999,768

SCREENING DEVICE Filed March 13, 19:51 2 Sheets-Sheet 1 April 30, 1935.c. s. LINCOLN SCREENING DEVICE Filed MarOh lS. 1951 2 Sheets-Sheerl 2 EmM 4 ,muow

Patented Apr. so, 1935 '1,99$,768

UNITED STATES PATENT OFFICE SCREENING nnvrcn Charles S.-Lincoln,Wauwatosa, Wis... assignor to Allis-Chalmers Manufacturing Company,Milwaukee, Wis., a corporation of Delaware Application March 13,1931,Serial No. 522,354 11 Claims. (01. 209-326) This invention relates ingeneral to theart of; invention will be apparent from a considerationvibratory screen separators and relates more speof the detaileddescription and of the drawings ciiically to an improvement in a singledrive accompanying the specification and forming a shaft screeningdevice provided with an eccentric part thereof on which like or similarreference having means for mounting a single screen or a charactersdesignate the same or similar parts 5.

plurality thereof and arranged to impart vibraor elements throughout thevarious views. tory movement to said screen. Fig. Us a plan view of avibratory, single-drive More specifically this invention has for one ofshaft screening device having the improved reits objects to provide aresilient rod support for silient rod support associated with an endportion an end portion of the screen of a vibratory screenof thevibratory screen thereof. 10

ing device as related above, said rod support per- Fig. 2 is a sideelevation of the device shown mitting a ready adjustment of theinclinationof in Fig. 1 and clearly illustrates the resilient susthescreen with respect to a frame on which the p n means connected to thefour corners of vibratory drive shaft and means cooperating therectangular frame of the device.

25 therewith is carried. Fig. 3 is a vertical cross-sectional view takenl5.

7 Another object of the invention is' to provide along line III-J11 ofFig. 1, looking in the direca vibratory screening device as relatedabove and tion of the arrows. having a substantially rectangular framesup- Fig. 4 is a sectional detail view of the means for ported byresilient means and having a motor for adJustably securing the resilientrod support to driving the vibratory shaftthereof mounted at thevibratory screen, taken along line IV-IV of 20 one side of said framewith counter-weights at- Fig. 3, looking in the direction of the arrows.tached to an opposite side of said frame' to Fig. '5 is a verticalcentral broken cross-section counterbalance the effect of said. motorand retakenalong line V--V of Fig. 1, looking in the lated elements andto. maintain the eccentric drive direction of the arrows. I

shaft in the desired horizontal position. Fig. 6 is an elevational viewof a flywheel shown 25 7 Another object of the invention is to provideon the eccentric drive shaft in Fig. 5 and shows 7 asingle shaftvibratoryscreening device adapted the balancing plates attached theretoin dotto carry one or a plurality of screens with im dash lines.

proved balancing flywheels having adjusting Fig. 7 is an elevationalview of a modified form means for' selectively counterbalancing the offlywheel assembled for three screen or three 30 screening device tocompensate for the particular deck operation of the improved vibratoryscreen- I number of screens carried by the screening device. ing device.

Another object of the invention is to provide a a Fig. 8 is across-sectional view of the flywheel vibratory screening device withimproved beartaken on the broken line VIII-VIII of Fig. '7.

3.5 ings for carrying the vibrating shaft mechanism, Fig. 9 is a view ofa portion of a side plate of the attached to the vibrating screen bodythereof screen body taken substantially in the plane of and to thesupporting frame through the use of Fig. 5 and shows a modified form ofmeans for ball and socket, self-aligning housings surrounddetachablysecuring a. reenforced screen within -ing the anti-friction bearings inwhich the vithe screen body while simultaneously permitting 40 bratingshaft mechanism operates. of the tensioning or stretching of the screenele- 40 Another object of the invention is to provide ments in thetransverse direction. I a vibratory screening device, preferably havinga Fig. 10 is a partial plan view of the spring rod as supporting frame,a vibrating shaft mechanism shown in Fig. 1 modified in this that aplurality rotatably associated with said frame, and having a ofintermediate clamping means for clamping the screen body secured atsubstantially its midspring rod to the vibratory screen body are pro- 45length to said vibrating mechanism in a manner vided. v permitting thedissociation of the vibrating shaft Fig. 11 is a fragmentary side viewof the frame mechanism as a unit from the device without disportionofthe screening device shown in Fig. 1 mantling or disturbing the screenb'ody. provided with resilient means for supporting the I Another objectof the invention is to provide a frame at its four corners from aninclined rigid 50 transverse spring rod end-support for a singlesupport.

drive shaft type of vibratory screening device Fig. 12 illustrates theeccentric bearing porwhich is simple in construction, durable and eftionwith respect to the remaining concentric fective in accomplishing thedesired results. portions of the drive shaft i8, said figure being Otherobjects and advantages'of the present referred to Fig. 5 and beingillustrated as showing eccentric bearings, which the relation when theshaft I8 is viewed looking in the line of its axis from the left end ofFig. 5.

Reference numeral 34 designates a rectangular frame shown includingstructural steel I-beam side members II and the end members thereof maybe L-bars connected by gusset plates at the ends to form a rigid frame.On the frame 34 is mounted at one side thereof, a motor 4| having adrive sheave which receives a plurality of endless V-belts for driving asheave 3| fixed to one end of an eccentric drive shaft l8 having endbearing portionssecuring the shaft rotatably with respect to the frame34. These end bearings comprise outer roller bearing-base members I,cooperating roller bearing caps 2, self-alining roller bearing housings3, inner sealing plates 4, an outer sealingplate 58 shown at the left inFig. 5, an outer bearing cover 5, outer roller bearing spacing collars6; a retaining washer l9 at each end of the shaft, a roller bearing 8 atthe left end of the shaft, see Fig. 5, of the floating type, acorresponding roller bearing 41 at the right end of the shaft l8, of theretainer ring 10- eating type. A sleeve 30 spaces the sheave 3| from theadjacent spacing collar 6, and said bearings are provided with openingsat I to receive "Alemite or other suitable fittings for lubricatingthe-same. Adjacent the outer bearing portions of the drive shaft l8 areflywheels 20 designed and provided with means for counterbalancing theeffect of the eccentric mounting of the drive shaft and the screen bodyeccentrically carried thereby, and including means for detachably andselectively receiving balancing blocks 2| to adjust saidcounterbalancing in accordance with the number and weight of screenscarried within the screen body. These flywheels will later be describedin detail.

Portions of the shaft l8 inwardly of the flywheel shaft portions areprovided with eccentric journals having their throws in the samedirection which is illustrated as being downwardly in Fig. 5. Thebearing for each eccentric of the drive shaft l8 includes an eccentricroller hearing base 9, an eccentric roller bearing cap l0 andaself-aligning roller bearing eccentric housing I I. The eccentricbearings are held spaced, in conjunction with innermost shoulders on theshaft l8, by a sealed spacing tube l4 surrounding the shaft l8. Thespacing tube M has integrally formed therewith, as by welds 300, annularflanges I04 engaging with adjacent ends of eccentric bearings l5- and I6and engaging with the selfaligning roller bearing housings I l to whichhousings the flanges I04 are bolted, by bolts not shown, to prevent allforeign matter from reaching the bearing ends are located closest to theatmosphere most highly saturated with foreign fine materials about thescreen. The spacing collars l3 on the shaft l8 space also each flywheel20 from the adjacent eccentric roller bearing. Reference numeral I2thereof against which represents eccentric roller bearing sealing platescooperating with the spacing collars l3. The ecshown at'the left in Fig.5 is preferably of the locating type whereas the similar eccentricroller bearing l6 shown at the right of Fig. 5 is preferably of thefloating type. Reference numeral 59 designates the eccentric rollerbearing inner, spacing collars which abut the innermost shoulders of theshaft l8, the shaft being eccentric only in those portions between theseinnermost shoulders and the shoulders the hubs 95 of the flywheels 20are shown to abut in Fig. 5.

The screen 13 of which a plurality, parallelly spaced, are shown on thefigures are carried through means of certain elements, later to bedescribed, by the eccentric roller bearings on the drive shaft l8. Inshort, the screens 13 may be said to be mounted within a screen body 22which partakes of the 'gyratory movement set up by the eccentric driveshaft l8 which participates in its support. The screen body 22 comprisesspaced side plates 23 carrying at the upper portions thereof andattached to their outer faces angle irons or bars 14. The side plates 23are suitably reenforced transversely by means of spaced stiffening irons8|. Within the screen body in spaced relation and rigidly attachedthereto are pairs of side angle irons 85, forming slides for the screenframes 24 and 60'. The pairs of angle irons support an upper coarse wirescreen 13 and a lower fine wire screen 13, the screens being slid intothe screen body 22 from the low end thereof. The opposite end of thescreen body may be closed. In order to facilitate ready removal of thescreens 13 the screen frames 24 and 60 to which the screens 13 aresecured by means of side screen frame bars 29 clamped by means of boltsto the screen frame, are held in place by means now to be described. Theside plates 23 of the screen body may be provided with struck-out rightangular portions 83 each portion having a vertical slot 84 in one legthereof for adjustably receiving, to take care of varying thicknesses ofscreens 13, a carriage bolt 26 carrying a screen frame clamping bar 25engaging at its lower edge a frame bar 23 and at its upper edge an innersurface portion of the screen body. From this it is evident that bydriving home the nuts on the carriage bolts 28 the screen frames 24 and60 will be rigidly yet detachably supported within the screen body '22.It is, of course, understood that instead of pressing out these rightangular portions from the side walls 23 that the same may be providedwith openings properly located to be covered by short angle irons 86,preferably welded to the side plates 23, and serving the same purpose asthe shown struck-out angular portions 83 in Fig. 5. A modifled means forreadily securing the screens I3 within the screen body is shown in Fig.9. This means contemplates a screen having slotted screen reenforcingside members 88 between which and a pair of bars 29'the side portions ofa screen 13 are clamped by means of suitable bolts, the slots in members89 being provided so that the heads of the clamping bolts are entirelywithin the cross-section of said members 88 and free from the angleirons 85. A short angle iron 86 having a vertical slot 84 in the lowerleg member thereof is positioned to cover each opening in the sideplates being preferably welded thereto, said slotted leg portionadjustably receiving, to take care of varying thicknesses of screens 13,a carriage bolt 26 having on it a combined clamping and tensioning bar81. Each clamping bar 81 is provided with 9. lug 88 welded thereon whichprecludes the lower end portion of a bar 81 from gouging into the screen13 when the nuts on the carriage bolts 26 are driven home, to rigidlyhold the side members 89 against the supporting angle irons 85, whilepermitting the tensioning of the screen elements I3 by reason of theoutward slidmg movement of said side members 89 on the anglev irons 85.

, Another feature of this invention resides in that the angle irons orbars 14 secured to the upper outer surface portions of the screenbodyside plates 23 detachably receive the eccentric shaft bearing andhousing portions to which these parts are attached by means of throughbolts 19. The eccentric drive shaft l8 and parts rotating therewith, orin other words the vibrating shaft mechanism is therefore detachable asa unit without disturbing or dismantling the screen body 22. The outerbearings for the shaft l8 are similarly secured to the frame 34 by meansof bolts 82, 'so that the vibrating shaft mechanism may readily bedetached as a unit from both the screen body 22 and from the frame 34without disturbing or dismantling the screen body. Reference numeral 80designates locating bolts for the eccentric bearings. I

The vibrating shaft mechanism suspending the screen body 22 atsubstantially its midlength from the frame 34 would make the screen bodytend to turn with respect to theframe 34. In order to prevent thisrelative rotation the improved spring rod support which constitutes animportant feature of this invention is provided either at the feed'endof the screen body or at its discharge end as shown on the drawings orat both ends. Now referring especially to Fig. 3 and 4 in which thearrangement of the improved spring rod support means for adjustably' andresiliently supporting an end portion of the screen 13 from the frame 34is shown in detail. The side plates 23 adjacent the low end and innerupper portions thereof are provided with angle irons 64 which support anangle iron crosspiece 62 substantially in the plane defined by theparallel upper edges, the side plates 23 or above said plane to allow ofsufficient clearance for large materials to be discharged from thescreen. The flange thereof which engages the angle irons 64 is directedaway from the shaft l9 and the upwardly directed flange of the angleiron crosspiece 62 is secured to a spring rod 35 through means to bedescribed later. An adjusting plate 63 is substantially centrallysecured to the crosspiece 62 and is provided with a vertical slot andthe upwardly directed flange of the angle iron cross-piece 62 isprovided with cut-away portions bounding said slot to receive a springrod clamp-.

ing block plate 38. It is to be understood, however, that the separate.adjusting plate may be formed as an integral part of the angle iron 62by extending its height, thuseliminating a separate element. The centralportion of the spring rod 35 is shown provided with clamping blocks 36grooved to receive the spring rod 35. The portion of the rod 35 withinthe blocks 36 is preferably surrounded by a rubber or other resilientsleeve 16 and permits of a clamping action on the rod 35 by means ofclamping bolts 12 received within transverse bores in the blocks 36 toeffect said clamping action. The bolts 12 carry the plate 38 which issuflicielntly large to lap the slot in the adjusting plate 63 and topermit of a secure fixation of the clamping blocks 36 to said adjustingplate 63 whenthe nuts on the bolts 12 are driven home. A pair of collars39 retained on the rod 35 .by set screws is provided on the intermediateportion of the rod 35 to prevent endwise movement of the rod 35 and toprevent displacement of the sleeve 16 within the blocks 36..

the blocks 31 to also prevent endwise movement of the rod 35 and toprevent displacement of the rubber sleeves within the blocks 31.

The width of the screen body may be such as to make it desirable to havea plurality of intermediate clamping connections between spacedadjusting plates 63 forming a part of the screen body 22, and the springrod 35. Such an arrangement is clearly illustrated in Fig. 10. In thisway a sufficiently resilient support may be. provided for a screen bodyextended in width, without necessarily increasing the diameter of thespring rod as is apparent. 4

The operation of the spring rod 35 and how it permits closed circuitvibrations at the end portions of the screen to conform closely to thegymtory circular closed circuit movements of the cocentric bearings onthe drive shaft I8 is readily apparent from the above description of thegyratory screening device, as well as is the means cooperating with thespring rod support for permitting the ready adjustment of theinclination of the screen body 22 and therefore also the upper and lowerscreens 13 with respect to the supportingframe 34.

Now referring to Fig. 6 in which a flywheel 20 mounted on shaft l8 inFig. is shown in side elevation. Fig. 5 shows, as stated before, theeccentric throw in the downward direction and therefore the flywheelshave their heavy portions above the center of the shaft l8 and Fig. 6 isa related showing and therefore the radially enlargedrim portion 92 ofthe rim 9| of flywheel 29 is shown at the top. The web portion 90intermediate the rim 9| and the hub 95 is provided with three relativelylarge circular bores 96 whose centers may be on the same circle. Theintermediate bore has its center in a diametrical line passing throughthe keyway |91 in the hub, the keyway being shown located diametricallyopposite the throw of the eccentrics. The centers of the bores 96 ateach side of this intermediate bore are spaced equal distances from saiddiametrical line and are therefore necessarily spaced equal'distancesfrom a diametrical line at right angles to said diametrical line. Eachflywheel 20 machined on these abutments. There are abutments on eachside of the web 99 and a pair of like balancing plates cooperatessimultaneously with the abutments 91. The radially enlarged rim portion92 also provides a pair of abutments 94 at each side of the web 90 andthese are outlined by an elongated slot 93 to likewise permitsatisfactory casting and subsequent machining of said abutments and tosimilarly secure a complete. and firm engagement therewith of edges ofthe rectangular balancing plates 2 I. The bores 96 are provided toenhance the unbalance of the flywheels without adding to their weight.The operation of this form of flywheel is as follows: With no balancingplates 2| bearing against either of the stops 94 or 91 or applied to theweb portion 99 of the flywheels 29 the screening device is set for twoscreen or two deck operation. When it is desired to add an intermediatescreen or deck to the screen body 22 all that is necessary to be done isto take a pair of like balancing rectangular plates 2| and cause theirlongitudinal edges to bear firmly against the .is provided with stops orabutments 91 at each side of the intermediate bore 96 and has slots 98abutments 94 and against which they may be held by means of boltspassing through holes 99. On the other hand, if it is desired to operatethe screening device with only one screen I3 or deck in the screen body,the pair of balancing plates is removed from its position just describedand similarly associated with the stops 91 as shown in Fig. 6 and heldthereagainst by means of bolts passing through other holes 99. Aflywheel under the arrangement stated should ordinarily balance when acounter-weight equivalent to a certain number of inch pounds dependingupon the weight and arrangement of screen body is placed diametricallyopposite the heavy side of the flywheel in line with the key seat. Forexample, a required counter-weight may amount to 129 divided by12 equals19 pounds, if placed at a radius of 12 inches.

The flywheel just described being castfrom metal is relatively expensiveand therefore the flywheel I29 formed of rolled steel plate andcomprising a disk as shown in Figs. '7 and 8 is preferred. Thissteelplate material makes a flywheel constructed therefrom ratherinexpensive as compared to a flywheel cast in the form shown in Fig. 6.The flywheel I29 similarly to the fly-- wheel 29 shown in Fig. 6 isprovided with large circular bores I96 winch may be of a smallerdiameter than the recessed circular bores I98 located in a diametricalline passing through the keyway I91 and which may have their centers onthe same circle as the bores I96. The face of a flywheel I29 oppositethe bores I98 is recessed, as shown at 299, to receive the heads ofbolts 29I passing through apertures concentric with the bores I99 withinthe flywheel, each of said bolts 29I selectively securing a balancingdisk I99 of a suitable length or lengths of shafting or disks within thedesired bore I98. The bores I96 similarly tothe bores 99 of the flywheel29, shown in Fig. 6, are ,equally spaced from the diametrical linedefined by the centers of the bores I98 and' they are likewise equallyspaced from a diametrical line at right angles to said diametrical line.The operation of this preferred form of flywheel is apparent from adescription of the operation of the flywheel shown in Fig. 6. With twoscreens I3 within the screen body 22 neither recessed bore I98 willcontain a balancing disk I99, while if an intermediate screen is addedto the two screens shown within the screen body 22, a balancing disk I99is inserted in the bore I98 adjacent the keyway I9I. On the other hand,if only one screen I3 is contained within the screen body only the otherbore I99 will receive a balancing disk I99.

In order to enhance the efficiency of operation of the disclosedscreening device having a single, vibrating shaft and a spring rod-endsupported gyratory screen, and for practical reasons, an I- bolt 69 ispreferably secured to each corner of the frame 34 to receive the loopportion of a threaded U-bolt 91 carrying disks 98 provided withapertures to receive the leg portions of another inverted threadedU-member 61. The nuts cooperating with the threaded ends of the U-bolts91 and pressing against the adjacent disks 68 compress a helicalcompression spring I9 depending upon the weight of the frame 34' andparts carried thereby. A cable I5 is secured to each one of the upperU-bolts 61. The other end of which cable is attached to an overheadsupport. Should the frame 34 move vertically downward due to unusualshock of falling material on the screen I3 or to improper balancing ofthe vibrating mechanism the springs I9 would restrain this movement to acertain degree depending upon their strength and the compressionprovided therein. The springs I9 effect a very desirable cushioningaction on the overhead support and prevent dependent vibration of theframe 34 and therefore also of the screens I3, which it is understoodmay be perforated plates, with respect to the overhead support for thevibratory screening device.

In explanation of the use of springs I9 it may be stated that while thecounter-weights 2| or I99 on the flywheels 29 and I29, respectively,ordinarily take care of all unbalancing due to the weight of theeccentrically carried screens I3 and their carrying and supportingelements, the variations of the load carried on the screens during theoperation which cannot be maintained uniform at all times will causesome vibrations to be transmitted to the supporting frame 34 and theseare taken care of by the springs I9, instead of being transmitted to theoverhead support and from there throughout the building.

In some cases it may be desirable to support the frame 34 resilientlyfrom inclined fixed supports I99 as illustrated in Fig. 11. This may beaccomplished by locating an inclined upper telescoping socket member loland a lower cooperposition the drive shaft I8 out of the horizontal andthereby effect unequal screening actions in transverse portions of thescreens I3. In order to preclude this possibility and to maintain auniform transverse disposition of the screening material on the screensI3, counter-weights 19 are attached to the web portions of the I-beam IIopposite the I-beam II which directly supports the motor 4 I. It will benoted that the center of gravity of the counter-weights I8, at thepreferred inclination of the frame 34, is in a vertical plane parallelto the axis of the drive shaft I8 and passing substantially through thecenter of the driving motor, to properly effect said counterbalancingaction thereby, since the supporting frame 34 must necessarily beoperated in z. position longitudinally inclined to the horizon- A feedhopper 11 shown in dot-dash lines at the elevated -or feed end of thegyratory screening device in Fig. 2 may be employed to conduct thematerial to be graded on to the upper screen I3 whereupon the gyratoryaction of the screen body 22 will effect the classified grading desireddepending as to whether one, two or three or more screens I3 are carriedwithin the screen body.

The disclosed gyratory screening device permits ready disociation of theeccentric drive shaft body. The improved flywheels effect and facilitatea selective balancing against the eccentriccarried screen body with thescreen body carrying one or a plurality of screen frames. The spring rodsupport permits of-readily adjusting the inclination of the screen bodywith respect to the supporting frame while permitting in-each adjustedposition a desired closed circuit vibration of the screen body andtherefore also the screens 13 at that end portion of the screens andeffectively precludes the relative rotation of the screen body withrespect to the frame 34 when the screening device is in operation. Theresilient support means for the frame 34 prevents dependent vibrationbetween the supporting members for the screening device and the frame 34and-the counter-weights l8 cooperate with such supporting means for thescreening device to maintain the single gyratory shaft of the screeningdevice in the desired horizontal position. Each of these features isconducive of enhancing the efficiency and value of this screening deviceand is separately set forth in the following claims.

It should be understood that it is not desired to limit the invention tothe exact details herein shown and described, for various modificationswithin the scope of the claims may occur to persons skilled in the art.

It is claimed and desired to secure by Letters Patent:

1. In a vibratory screening device, in combination, a screen frame, anoperating eccentric about which said frame may pivot longitudinally andwhich participates in its support, a frame support for said eccentric,transverse resilient supporting means for said screen frame located at adistance from and generally parallel to the axis of rotation of saideccentric, said means being secured at its ends to said frame supportand at its middle to said screen frame and permitting of a closedcircuit movement of said screen frame in a longitudinal plane thereofand means for rotating said eccentric.

2. In a vibratory screening device, in combination, a screen member, anoperating eccentric about which said screen member may pivotlongitudinally and which participates in its support,

a frame support for said eccentric, transverse resilient supportingmeans for said screen member located at a distance from and generallyparallel to the axis of rotation of said eccentric, said means beingsecured at its ends to said frame and at its middle to said screenmember and permitting of a closed circuit longitudinal movement of saidscreen, means connected with said screen member-supporting meanspermitting of adjustment of the inclination of said screen member withrespect to said frame, and means for rotating said eccentric.

3. A gyratory screening device comprising, a frame, vibrating meansincluding a shaft provided with an eccentric, rotatably associated withsaid frame, means connected with said eccentric and partaking of itsmotion, a screen member secured to said means, flexible means comprisinga rod located remote from and generally parallel to said shaft andsecured to said screen member and to said frame, and permitting of asubstantially circular movement of said screen member, means connectedwith an intermediate portion of the rod of said flexible means,permitting adjustment of the inclination of said screen member withrespect to said frame, and means for rotating said shaft.

4. A gyratory screening device comprising, a

frame, vibrating means including a shaft provided with an eccentric,rotatably associated with said frame, means connected with saideccentric and partaking of its motion, a screen member secured to saidmeans, means comprising a flexible rod located remote from and generallyparallel to said shaft and clamped at an intermediate portion to saidscreen member and at its ends to said frame and permitting of a closedcircuit movement of said screen member, means connected with anintermediate portion of the rod of said remote means, permittingadjustment of the inclination of said screen member with respect to saidframe, and means for rotating said shaft.

5. A vibratory screening device, comprising a frame supported at aplurality of points, vibrating means including a shaft journaled to saidframe, means connected with said vibrating means and partaking'of itsmotion, a screen secured to said connected means, flexible meanspositioned generally parallel to and located remote from said shaft andsecured to said frame and to said screen, intermediate portions of saidflexible means being flexible in directions transversely of said shaft,said means permitting of a closed circuit movement of said screentransversely of said shaft, means connected with said flexible meansremote from said shaft permitting adjustment of the inclination of saidscreen relative to said frame, and means for rotating said shaft.

6. A vibratory screening device, comprising a frame suspended at aplurality of points, vibrating means including a shaft journaled to saidframe, means connected with said vibrating means and partaking of itsmotion, a screen secured to said connected means, means comprising'aresilient rod located, remote from and generally parallel to said shaftand secured at an intermediate portion to said frame and at its ends tosaid screen and permitting of a closed circuit movement of said screentransversely of said shaft, means connected with an intermediate portionof the rod of said means remote from said shaft, permitting adjustmentof the inclination of said screen relative to said frame. and means forrotating said shaft.

'7. A vibrating screen mechanism, comprising a frame adapted to carrythree screens, a shaft having eccentric portions operatively connectedto impart vibratory motion to said frame, means for rotatably supportingsaid shaft and for supporting said frame to permit vibration thereof,unbalanced flywheels secured on said shaft said unbalanced wheels beingso proportioned that they effectively counterbalance said frame when itis carrying two screens and being shaped to receive counterweights attwo predetermined positions, and counterweights for said unbalancedflywheels said-counterweights being so proportioned that when attachedto said flywheels at one of said predetermined positions the flywheelsbecome so unbalanced as to effectively counterbalance said frame when itis carrying three screens and when attached to said flywheels at theother of said predetermined positions the flywheels are so adjusted asto effectively counterbalance said frame when it is carrying only onescreen.

8. A vibrating screen mechanism, comprising a frame adapted to carrythree screens, a shaft having eccentric portions operatively connectedto impart vibratory motion to said frame, means for rotatably supportingsaid shaft and for supporting said frame to permit vibration thereof,unbalanced flywheels secured on said shaft said unbalanced wheels beingso proportioned and having their heavy sides so disposed that theyeffectively counterbalance said frame when it is carrying two screensand being shaped to receive counterweights at their heavy sides and attheir light sides, and counterweights for said unbalanced flywheels saidcounterweights being so proportioned that when attached to saidflywheels at their heavy sides the flywheels become so unbalanced as toeifectively counterbalance said frame when it is carrying three screensand when attached to said flywheels at their light sides the flywheelsare so adjusted as to effectively counterbalance said frame when it iscarrying only one screen.

9. A vibratory screening apparatus, comprising a supporting frame, ascreen vibrating shaft rotatably mounted on said frame, a screen elementpivotally carried by said screen vibrating shaft, and resilientsupporting means for said screen element including a resilient roddisposed substantially parallel to said shaft and spaced therefrom saidrod being attached at its ends to opposite sides of said frame andconnected to said screen element near the middle thereof.

10. A vibratory screening apparatus, comprising a supporting frame, ascreen vibrating shaft rotatably mounted on said frame, a screen elementpivotally carried by said screen vibrating shaft, and resilientsupporting means for said screen element including a resilient roddisposed substantially parallel to said shaft and spaced therefrom saidrod being attached at one end to said frame and connected to said screenelement near the middle thereof.

11. A vibratory screening apparatus, comprising a supporting frame, ascreen vibrating shaft rotatably mounted on said frame, a screen elementpivotally carried by said screen vibrating shaft, resilient supportingmeans for said screen element including a resilient rod disposedsubstantially parallel to said shaft and spaced therefrom said rod beingattached at one end to said frame and connected to said screen elementnear the middle thereof, and means associated with said rod foreffecting adjustment of the inclination of said screen element relativeto said frame.

CHARLES S. LINCOLN.

